1. Field of the Invention
This invention relates to check valves and more particularly, to a ball check valve including a valve cage having at least three rods longitudinally spaced in the cage wall and extending longitudinally into the cage interior for contacting the ball to prevent wearing of the cage wall and minimize ball wear when the ball moves back and forth in the cage responsive to fluid flow through the cage and check valve. In a preferred embodiment the rods are spaced equidistant from each other around the circumference of the cage interior and are rotatably disposed in respective rod cavities provided longitudinally in the cage wall. The rotating action of the contact rods presents a varying contact surface to the moving ball and thus prolongs the life of the contact rods, as well as the stabilized ball. In a most preferred aspect of the invention, eight contact rods are spaced equally around the circumference of the valve cage wall to guide the ball in its back-and-forth movement in the cage and prevent excessive ball oscillation. In a second preferred embodiment of the invention, the contact rods are fixedly mounted in the respective rod cavities.
2. Description of the Prior Art
Various types of check valves utilizing a movable ball are known in the art. U.S. Pat. No. 1,777,539, dated Oct. 7, 1930, to John A. Yerkes, discloses a "Valve Cage", characterized by an annular valve seat including two diametrically-spaced arms extending upwardly therefrom to mount on a spider joint. Two additional diametrically-spaced arms extend downwardly from the spider joint and terminate above the valve seat. The spider joint is centrally bored and provided with interior joint threads for engaging respective pipe threads provided on a pipe. A ball vertically movably disposed between the arms of the cage allows unidirectional flow of fluid through the valve seat, valve cage and spider joint and into the pipe threaded into the spider joint. The ball prevents backflow of fluid from the pipe through the valve cage by blocking the fluid opening in the valve seat. U.S. Pat. No. 2,085,360, dated Jun. 29, 1937, to David M. Hammett, discloses a "Pump Valve Construction" characterized by a cylindrical valve cage including a centrally-disposed fluid passage traversing the length thereof. A valve guide mounted in the passage includes an annular lower portion fitted tightly against the wall of the passage to effect a fluid-type seal with the passage. A valve seat is provided in the passage below the valve guide and a bushing is threaded into the lower end of the valve cage member to press the valve seat against the valve guide. Threads provided on the exterior circumference of the upper end of the valve cage allow threadable attachment of the valve cage to a pipe. A ball valve vertically movably disposed within the valve cage permits unidirectional flow of fluid through the bushing and valve cage and into the attached pipe. U.S. Pat. No. 2,274,968, dated Mar. 3, 1942, to Walter A. O'Bannon, details a "Blind Cage Valve", characterized by a cylindrical valve housing including a smooth internal bore. An annular valve seat positioned in the lower end of the bore has an axial fluid passageway extending therethrough. A ball valve is slidably disposed in the bore and a guide member slidably mounted in the bore is located in the upper end of the bore for receiving the upper portion of the ball valve. U.S. Pat. No. 2,937,659, dated May 24, 1960, to Jacob W. Harris, et al, describes a "Ball Valve Cage" including an elastomeric ball guide having an elastomeric projection or button fitted into a recess provided in the upper end of the valve cage, directly above an annular valve seat mounted in the lower end of the cage. Multiple, circumferentially-spaced guide elements extend downwardly from the elastomeric projection, abutting the walls of the valve cage. A valve ball is disposed in the valve cage between the guide elements, which serve to reduce wearing of the valve ball and the interior valve cage surface. U.S. Pat. No. 3,219,057, dated Nov. 23, 1965, to John G. Knowles, details "Check Valves", which include a cylindrical valve housing that accommodates a valve cage characterized by a single wire bent into a zig-zag configuration substantially circular in transverse cross-section with multiple, parallel, straight longitudinal portions having alternate end connection therebetween. A valve seat is provided on one end of the valve cage and a spring seated against the valve housing at the opposite end of the valve cage exerts pressure on a valve ball located in the valve housing, urging the ball to engage the valve seat. Unidirectional flow of a pressurized fluid is permitted through the valve seat and valve cage and out the opposite end of the housing. U.S. Pat. No. 3,724,496, dated Apr. 3, 1973, to Walter S. Secrist, discloses "Cage and Guide Construction for a Ball-Type Valve", characterized by a cylindrical valve cage including spaced-apart internal shoulders which have confronting grooves. Multiple guide pieces arranged in spaced relationship lie between the shoulders and have lips which engage the grooves to lock them in place. The guide pieces can be either metal or elastomer and are not distorted when inserted or removed. U.S. Pat. No. 3,827,122, dated Aug. 6, 1974, to Bobby L. Douglas, describes a "Check Valve Cage Apparatus and Method of Making Same", which check valve cage is fabricated by injecting a reinforced thermal setting plastic through a channel extending along the central longitudinal axis of a cylindrical body. A form pin is inserted through a coaxial longitudinal bore at the other end of the cylindrical body, the bore having an increased-diameter central portion for receiving the injected thermoplastic material. After the plastic material has set, lateral flow passages are formed in the wall of the cylindrical body. U.S. Pat. No. 4,091,839, dated May 30, 1978, to Verne P. Donner, details a "Ball Check Valve" characterized by a valve cage constructed of two spring wire pieces, each having two ball guiding legs attached by cross members formed with interfitting loops which hold the pieces together by spring tension. Each guiding leg is formed with a reverse bend extending outwardly and then rearwardly along the valve body walls, thus positioning the guide in the valve body. The cage is formed larger than the inside of the valve body in which it fits and also serves as a retainer for the ball valve spring. U.S. Pat. No. 4,243,067, dated Jan. 6, 1981, to Robert J. Rubey, details a "Ball Type Check Valve" characterized by a valve body including top and bottom flanges. The bottom flange is provided with inlet holes which are aligned with respective outlet holes provided in the top flange for fluid flowing through the valve. A ball is contained in the valve body and rests on a ball seat surrounding the inlet. A top plate positioned adjacent to the top flange has an opening therethrough which diverges concentrically toward the outlet opening and a ring-shaped ball stop which receives the ball when it is forced away from the ball seat by the fluid is positioned in the valve body, between the top plate and the top of the ball. U.S. Pat. No. 4,674,529, dated Jun. 23, 1987, to Sean M. Ferguson, discloses a "Check Valve" constructed of two housings or castings, each of which has a corrosion-resistant liner which provides improved support and operation of the ball or check member and increased resistance to linear collapse when operating under vacuum conditions.
Conventional ball-type valves generally utilize a valve cage which may be either of the close-side type, in which fluid enters one end of the valve and discharges at the opposite end, or of the open-side design, in which fluid discharges through slots in the sides. Because fluid is frequently pumped through the valve under high pressures and at high velocities and since ball check valves must be constructed of a wide variety of materials, there exists a need for the ball to be linearly guided as it moves within the cage, to prevent excessive oscillation and accompanying ball wear, as well as wear on the cage wall.
Accordingly, it is an object of this invention to provide a new and improved, low pressure drop ball check valve characterized by a valve cage having wall inserts which are resistant to the excessive wearing effects of the valve ball moving back and forth in the valve cage responsive to liquid flowing through the valve.
Another object of this invention is to provide a ball check valve characterized by long life, corrosion resistance and reduced maintenance and including a cylindrical valve housing containing a valve cage provided with multiple wear-resistant contact rods or members fixedly or rotatably mounted in spaced relationship with respect to one another around the circumference of the interior wall of the valve cage and extending longitudinally into the cage, for preventing excessive wearing of the valve ball and cage wall by receiving and linearly guiding the valve ball as it traverses the length of the valve cage responsive to fluid flowing through the valve.
Still another object of this invention is to provide a ball check valve having no welds and broad industrial application and including a valve cage characterized by multiple, wear-resistant contact rods fixedly or rotatably disposed in respective rod cavities shaped longitudinally in the interior surface of the valve cage wall in circumferentially-spaced, parallel relationship with respect to one another, which contact rods extend longitudinally into the valve cage, contact the valve ball and prevent the valve ball from excessively oscillating and wearing the ball and interior surface of the valve cage wall by guiding the valve ball as the valve ball traverses the valve cage responsive to fluid flow through the valve.